ADM2587E - 61000-4-4 (burst immunity issue)

We have a big problem with EMC imunity (EMI maybe also) with the ADM2587. The level of the immunity is very low, under 1kV and we do not know what to do, because we have already checked almost everything. The RS-485 transceiver is not resistant against the test IEC 61000-4-4 and IEC 61000-4-6 in our connection (schematic and layout). The communication drops down periodically when the test is asserted. In the attachment, you can see our schematic and layout. In the pdf, layer: TOP, GND, POWER, BOTTOM.